Field of the Invention
The present invention relates to a technique of generating, analyzing, and reconstructing print data.
Description of the Related Art
In recent years, improvements in speed and quality of digital printers have expanded a print-on-demand (POD) market. The POD is a service of printing electronic data using a digital printer and performing variable data printing (VDP) by utilizing characteristics of using electronic data. A document used in the VDP is divided into a fixed portion and a variable portion. Data in the variable portion is supplied from a data source such as a comma separated values (CSV) file. Different contents are printed by associating a column of the data source with the variable portion of a template document, and applying the association to each row (record) in the data source. Thus, there is an advantage that a printed product suitable for each client can be produced because contents of printing can be changed among clients. Herein, a set of logical information such as a page layout and a data source required for a single VDP is referred to as “VDP document” and physical electronic data related to the VDP document is referred to as “VDP data”. In many cases, a dedicated page description language (PDL) is used for the VDP data. The PDL dedicated to the VDP can be described in such a way that an object in the fixed portion in the VDP document (hereinafter, referred to as a fixed object) is defined in advance to be referred later. When print using the PDL is performed, a result of analyzing each fixed object is stored, and the result of the analysis processing is copied each time the fixed object is referred to. Thus, the processing for the entire VDP data can be executed at a higher speed. In other words, the PDL dedicated to the VDP can describe a VDP document that can be efficiently processed by an application analyzing VDP data.
As the PDL dedicated to the VDP, PDF/VT is available. Portable Document Format (PDF) has been widely used for print data. PDF/VT is the PDL based on PDF and thus is highly suitable for a workflow using PDF print data. However, there is a problem that PDF/VT needs to have a large amount of page information, and thus involves a large amount of data. More specifically, the number of records of data sources in the VDP is large in general, and thus the amount of page information is large. As a result, the data amount as a whole becomes huge. The page information includes data on graphics in a corresponding page and attribute information on the page.
Japanese Patent Application Laid-Open No. 2013-134748 discusses a method of dividing VDP data into print data and a data source and combining the print data and the data source when printing is performed. The print data includes page information for a single record and configuration information on a variable portion that dynamically varies among records. The configuration information on the variable portion is combined with the data source when the printing is performed. As a result, the amount of print data can be reduced to data for a single record.
However, the method discussed in Japanese Patent Application Laid-Open No. 2013-134748 requires special combining processing for converting the configuration information on the variable portion using the data source. In the VDP data format such as PDF/VT, the print data has the number of expanded page objects corresponding to the number of the records, and thus the data amount increases with the number of records. All things considered, special combining processing is required for performing printing with the print data, having the data amount reduced to that for a single record, while dynamically changing the print data for each record.
The present invention is directed to a technique for suppressing an amount of print data even when the number of records is large, and performing print processing without the special combining processing.